The prior art has taught self-watering planters in U.S. Pat. Nos. 4,329,815 and 6,134,833. Each of these prior art references teaches a planter with hollow walls, which store water and the use of a hydrophilic sensor, which is coupled via a tube to an air space above the water level in the reservoir. The hydrophilic sensor is buried in the soil and absorbs water from it. When the soil is dry, the sensor lets air pass through it, which lowers the vacuum level in the air space above the water. When this vacuum level is decreased, gravity and hydrostatic pressure force the water out an exit hole in the reservoir and into the soil. When water in the soil reaches the sensor, the sensor absorbs some of this water and becomes impenetrable to air. When the sensor becomes inpenetrable to air, the sensor no longer vents the space above the liquid in the walls of the planter to the atmosphere and causes the vacuum level to rise as water continues to flow out, and creates more free space at the top of the reservoir. When the vacuum level reaches a high enough level, water stops flowing. The cycle repeats when the plant consumes enough water to dry out the soil and causes the hydrophilic sensor to become passable to air again.
This system works well, but there are a very large number of sizes and shapes for planters, and to make all these sizes and shapes as self-contained, self-watering planters is impractical in the tooling costs to create tools in which to do the necessary rotational or injection molding. Thus, making every necessary size and shape of self-watering planter using the technology of U.S. Pat. No. 6,134,833 is impractical.
In many companies and other buildings, freestanding concrete or fiberglass planters, or built-in planter beds, are used to hold dirt in which decorative plants are planted to dress up the atmosphere of the building. These planters can be of any size and shape. Frequently, they are placed in locations where there is no access to water pipes so as to enable use of automatic irrigation systems to supply water to the plant. This results in a need for frequent manual watering of the plants by company employees, or the need to hire a plant care service to make frequent visits to make sure the plants are getting enough water. This is a nuisance and is expensive. Further, if the employees fail to water the plants frequently enough, or supply too much water, the plants can die or not prosper. Further, typically, when employees water plants, they keep pouring water into the planter until they see water appear in the saucer below the planter. At that point, the combination of water already in the saucer and in the soil is greater than the capacity of the saucer, which will cause overflow of the saucer and create slip-and-fall liability exposure. The same thing happens if an automatic irrigation system has its water time set for too long an interval. Since large plants used in large planters are generally more expensive, failure to properly water them can result in undesirable and costly losses among the plant population.
In the prior art, building owners have attempted to run underground water pipes to the locations of the freestanding planters to enable use of automatic sprinkler systems. The problem with this approach is that it fixes the location of the planter such that once the pipe is run, the planter cannot be moved to another location without a costly, disruptive relocation of the underground pipes. Further, if pipes are run under sidewalks or flooring, any leaks in the pipes can damage the flooring materials or wash away earth, serving as foundation for the sidewalk or get in the cracks in the flooring or sidewalk, and causes damage such as cracking when freezing, resulting in expansion of leaked water occurrence. Leaked water from a cracked pipe or overflow by an automatic sprinkler system of xe2x80x9csaucerxe2x80x9d overflow containment reservoirs placed below freestanding planters can cause slip-and-fall liability exposure to building owners.
Further, in many new multi-use high-rise buildings with commercial offices on the lower floors and residential space on the upper floors, zoning requirements or living condition considerations often give rise to the need for a garden zone in the building. This is often placed on the roof. This creates a problem in running water pipes to the greenbelt zone on a rooftop because owners are hesitant to penetrate the waterproofing of the roof to run pipes up to the rooftop garden. Further, a burst pipe on a rooftop can result in large damage awards for water damage to residential and businesses below the rooftop garden.
There are several other modular reservoir products on the market now, which are buried in the planter dirt to supply water to the plant(s). These prior art products consist of a single hollow container, which is filled with water and buried in the soil at the bottom, or part way up from the bottom. Also, in the prior art, multiple units have been linked together with flexible tubing for larger applications. A fill tube sticks up through the soil for filling. The container has an outlet, which allows water to be drawn out into the surrounding soil by capillary action. The water continues to wick out of the container until the soil is saturated, and capillary action no longer draws water out of the container. These products have reservoirs, which are too small, and the water system does not regulate flow of water to the plants on an as-needed basis, but on a saturation basis. As a result, problems arise with the reservoir running dry and with the plants getting too much water or not enough. Saturation soaks the soil, which puts the plant under stress and causes growth of anaerobic bacteria in the bottom of the planter, which causes a bad smell. Further, the small reservoirs cause the need for frequent maintenance visits, which drives the cost to the customer up, and this problem is exacerbated by the fact that the prior art devices are supplying the plants with far more water than they actually need for good health. Other approaches, such as false bottom containers with reservoirs below the false bottom with wicks that go up in to the soil above the false bottom. These approaches also saturate the soil and cause stress to the plant and the growth of bacteria and smelly planters. As a result, these products have not been commercially successful.
Accordingly, a need has arisen for an irrigation insert, which solves all the above-noted problems. The multiplicity of sizes of large containers in all materials make producing self-contained units, as taught in plant U.S. Pat. No. 6,134,833 for all sizes impractical. There are thousands of variations of sizes and shapes of planters and containers. An apparatus is needed which provides the self-watering advantages of U.S. Pat. No. 6,134,833 but overcomes the drawback of the need for thousands of different sizes and shapes. The apparatus should be a single system which can, with a limited number of parts, provide a self-watering solution for a broad array of container size and shapes including containers that are not self watering and for which plumbing a water line thereto would be impractical or undesirable for other reasons.
The above-described needs are filled by a modular plant water reservoir, which is buried in a planter and which stores water therein, which is metered out into the soil using a hydrophilic sensor that the plant only gets the water it needs to prosper. The reservoir is modular in that it is comprised or a plurality of individual sections. Each section has an upper port and a lower port. All the upper ports are coupled together by hoses or tubing, which form an airtight passageway so that all the upper portions of the reservoirs are in fluid communication with each other so that the pressure in each reservoir upper portion is the same as in every other section. The lower ports are also coupled together by hoses or tubing that form a watertight passageway so that water in each section can flow to the other sections so that the water level in each section is the same. At least one of the sections has a fill tube, which is long enough to extend above the top surface of the soil when the modular watering system is buried.
At least one of the sections has an air hole located in a wall of the section so as to be above the water level when the modular watering system is filled with water. This air hole is coupled by a hermetic seal to a flexible air tube, which has, at its other end, a hydrophilic sensor/plug, which only lets air into the tube when the soil is too dry and the plant needs more water.
The hydrophilic sensor only allows enough water to enter the soil until there is enough water in the soil to cause the hydrophilic sensor to become airtight. When the hydrophilic sensor becomes airtight, it cuts off airflow into the top of the reservoir. The water continues to flow out the bottom outlet holes briefly until the falling water level creates a sufficient vacuum level in the top of the reservoir to stop further flow of water into the soil through water outlet holes in the bottom of the reservoir.